If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Swapping lenses in a Petzval

About the only project I completed this Summer was one involving an 8x10 Petzval lens that I picked up from Eddie. I made some adapters for it so that I could mount the lenses in a shutter in various configurations. I thought you'd like to see the results.

I took two sets of photos, one close and the other at a distance. I didn't get around to doing any at portrait distance, however.

I started with the cemented doublet in front, and the flint & crown pair in the back. The first photos are with the original Petzval design, i.e., flint forward, crown in the rear. The second are with the flint and crown reversed in the rear (the Dallmeyer flip).

Next I removed the doublet from the front, and used only the flint/crown pair in the rear, reversing the order of the two lenses.

Lastly, I mounted the flint and crown lenses separately, at barrel-length from one another, reversing their order also.

I'll put the photos in separate posts, so that I can mark them appropriately. My apologies for the differing exposures - most were guesses.

Re: Swapping lenses in a Petzval

I'd like to know more about how you adapted the lenses to a shutter. Did you take the lens out of the originial brass (assuming) barrel and then mount them in a homemade barrel on both sides of the shutter?

Re: Swapping lenses in a Petzval

Charley--Interesting post! I'm curious as to the focal length and maker of the lens. It looks more like a half plate lens from the coverage on your film. Also, the very first comparison with flipping the rear group (ala Dallmeyer) is curious. Is the first (traditional) configuration the native configuration of the lens? That would be odd because it looks like that configuration is incorrect by the results. Reversing the rear group clearly makes a huge difference in the sharp coverage of the lens and yields the traditional swirly highlights around the edges of the field.

Re: Swapping lenses in a Petzval

Originally Posted by domaz

I'd like to know more about how you adapted the lenses to a shutter. Did you take the lens out of the originial brass (assuming) barrel and then mount them in a homemade barrel on both sides of the shutter?

Short answer: yes. The glass is still sitting in the original brass mount, but that mount has been unscrewed from the barrel. The size of the adapters, of course, is important.

Here's a picture of the lenses in the original barrel, and one of them mounted in a shutter. The knurled brass piece on the front lens is an adapter to allow 77mm filters to be used.

Re: Swapping lenses in a Petzval

Originally Posted by BarryS

Charley--Interesting post! I'm curious as to the focal length and maker of the lens. It looks more like a half plate lens from the coverage on your film. Also, the very first comparison with flipping the rear group (ala Dallmeyer) is curious. Is the first (traditional) configuration the native configuration of the lens? That would be odd because it looks like that configuration is incorrect by the results. Reversing the rear group clearly makes a huge difference in the sharp coverage of the lens and yields the traditional swirly highlights around the edges of the field.

Yep, the whole project is interesting and the results are all curious - lots of fun.

I haven't measured the focal length; it's fairly short, probably less than 6 inches. The focal length using the Dallmeyer arrangement is somewhat longer than the Petzval arrangement. Calling it an 8x10, of course, is a sleazy lens-seller tactic

There are no markings on it, so I have no idea about maker, and there's no way of knowing in what configuration the lens left the factory.